Electric vehicles using electricity as the source of power are in widespread use. A user can charge a storage battery installed in the electric vehicle, for example, by using charging equipment located at the residence of the user. Patent Literature 1 teaches a device, capable of scheduled charging of a storage battery during charging of an electric vehicle.
Meanwhile, home energy management systems (HEMSs) are in wide use for control of the supply of electric power to home electric equipment. More stable and economical supply of electric power becomes possible by combination of the electric vehicle with the HEMS, and rather than just increasing convenience of the electric vehicle for the user, such combined use is also anticipated to increase reliability of the HEMS.